The present invention relates to a position adjusting device for steering wheels which provides optimal conditions for the driver through appropriate adjustments. More specifically, the present invention relates to a position adjusting device for steering wheels providing for both the tilting/telescoping of the steering wheel as well as for adjustment of the incline of the rotating surface of the steering wheel.
Various steering devices having tilting and telescoping features have been developed in the past. Japanese patent publication number 48-33567 discloses a fixing slot along a Y--Y direction extending parallel to a steering wheel bracket fixed to a vehicle. A second fixing slot along an X--X direction roughly perpendicular to the Y--Y direction is formed on a stay that is integral with a housing. A middle shaft and a lower shaft connect with a universal joint. An upper shaft attaches to a steering wheel.
The middle shaft and the lower shaft are meshed via splines which allow motion in the Y--Y direction. Thus the steering wheel can be simultaneously adjusted in the X--X direction and the Y--Y direction.
For this adjustment, the connection section of the universal joint interposed between the upper shaft and the middle shaft serves as the support section (pivot). This support section is positioned on the axis of the middle shaft, which moves only in the Y--Y direction while it remains stationary in the X--X direction (i.e., extends and retracts in one direction only). In other words, the support section is displaced only in the axial direction while remaining stationary in the axial sliding direction.
In Japanese laid-open utility model number 62-130947, a device adjusts the position of a steering wheel up and down or forward and back. A middle shaft connects a column shaft and a steering gear. A connecting section capable of moving solely in the axial direction is mounted on the middle shaft. When the column shaft is adjusted up and down or forward and back, the middle shaft extends and retracts while also pivoting.
In Japanese utility model publication number 2-24366, the tilting/telescoping adjustment device rotates in tandem with a middle shaft, which extends and retracts axially. A support section is disposed below the column and is displaced along the axis of the steering shaft.
In Japanese laid-open utility model publication number 48-14729, slots extending up and down are disposed on either side of a position fixing screw on a bracket toward the car, while slots extending front and back are disposed on the bracket toward the column near the steering wheel. A support opening is disposed opposite and below these slots so that front and rear support sections are kept from moving forward or backward. These support sections are only allowed to be moved up or down (along the axis of the shaft).
In Japanese utility model publication number 60-37891 and Japanese utility model publication number 59-41895, mechanisms that allow tilting with simple structures are described.
In the conventional technologies described above, the devices presented adjust the steering wheel position both up and down and forward and backward. When the up/down and forward/backward adjustments are made so that the support section below the column is moved in tandem with the column shaft, the position of the support section is not restricted. Thus, free adjustments are allowed to be made over a wide range.
However, the position of the support section changes only based on where the vertical and horizontal slots are combined. Thus, the vertical slot position relative to the horizontal slot formed on the bracket, i.e. the adjustment of vertical pivoting, can be performed solely along the slots.
If the steering wheel is to be positioned up or down from a forward or rear position, the adjustment must be made within the vertical pivoting range centered on the support section. This makes it difficult to freely select an optimal position suited to the physical characteristics of the driver.
Further optimal positioning can be provided if it were possible to make fine adjustments in the incline of the rotation surface of the steering wheel, thus providing comfortable steering conditions for the driver. However, in the conventional structures, fine adjustments are unable to be made to the steering wheel. Adequate adjustments for optimal positions is not possible is these conventional structures.
In the conventional structure, the support section is positioned below the column and adjustments to the steering wheel are performed along horizontal and vertical slots in a single direction. Consideration was not made to provide adjustments for upward or downward inclines of the steering wheel in addition to the vertical pivoting of the steering wheel. Furthermore, there was no consideration made at all to provide fine adjustments to the steering wheel plant using this structure (for providing up/down adjustments around the support section). Also, making this type of structure simple would prove difficult.
For example, changing the incline of the rotation plane of the steering wheel using the conventional structures as a base, a spherical bearing could be added to the attachment section between the steering shaft and the steering wheel to move the steering wheel plane. However, adding this kind of structure makes the device that much more complex, increasing the number of parts, and making the device more expensive. Also, making the device compact and light becomes difficult.
Based on the above, it can be seen that the conventional technology does not provide a structure for adjusting the rotation plane of the steering wheel in a device for adjusting the tilting and telescoping. Thus, there is a need for the development of a new steering wheel that allows easy adjustment of the incline of the steering wheel rotation plane using a tilting/telescoping adjustment device.